5.3.A

Math5th GradeNumber and operations

The Standard

estimate to determine solutions to mathematical and real-world problems involving addition, subtraction, multiplication, or division

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students estimate answers to addition, subtraction, multiplication, and division problems. They choose useful rounded or compatible numbers and use the estimate to judge whether an answer makes sense.

What Mastery Looks Like

Students choose rounding or compatible numbers that fit the problem. They compute mentally, label the answer as an estimate, and explain why it is reasonable.

Common Misconceptions

Students may round every number to the same place even when that gives a poor estimate. They may choose the wrong operation, report an estimate as exact, or use numbers that are not easy to compute mentally.

How to Assess It

Give this exit ticket: “A school orders 47 boxes with 198 pencils in each box. Estimate the total and explain your number choices.”

Lesson moves

Ways to Teach It

  1. Give pairs number cards and operation cards, then have them build a problem and replace each number with a useful rounded or compatible number.

  2. Ask, “Which is a better estimate for 398 ÷ 19, 20 or 200?” Students defend their choice in two sentences.

  3. Play Estimate Match by having students pair exact-expression cards with estimate cards, then explain one match to a partner.

  4. Use a grocery flyer to estimate the cost of several quantities, such as six cereal boxes or three pounds of apples.

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